Commit 06719814 authored Apr 28, 2008 by Atsushi Nemoto Committed by Linus Torvalds Apr 28, 2008

atmel_spi: support zero length transfer

A spi transfer with zero length is not invalid.  For example, such
transfer (len == 0 && delay_usecs != 0) can be used to achieve delay
before first CLK edge after chipselect assertion.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent b687d2a8

drivers/spi/atmel_spi.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -616,7 +616,7 @@ static int atmel_spi_transfer(struct spi_device spi, struct spi_message msg)
		return -ESHUTDOWN;

		list_for_each_entry(xfer, &msg->transfers, transfer_list) {
		if (!(xfer->tx_buf \|\| xfer->rx_buf)) {
		if (!(xfer->tx_buf \|\| xfer->rx_buf) && xfer->len) {
		dev_dbg(&spi->dev, "missing rx or tx buf\n");
		return -EINVAL;
		}